Method and Apparatus for Cognitive Radio Coexistence

ABSTRACT

In a non-limiting and exemplary embodiment, a method is provided for sharing secondary cognitive radio resource user related information. A coexistence node receives information on network properties associated with secondary cognitive radio resource users. An upload message is generated and sent, the upload message including for a secondary user database at least information on the received network properties associated with secondary cognitive radio resource users. A location-dependent network map including at least information on network properties is generated. The network map is sent to assist one or more secondary cognitive radio resource users.

FIELD OF THE INVENTION

The present application relates generally to cognitive radiocoexistence.

BACKGROUND OF THE INVENTION

Cognitive radio refers to a radio device which can intelligently detectwhich communication channels are in use by primary users and which arenot, and move into vacant channels while avoiding occupied ones.

An important function of cognitive radios is spectrum sensing, generallyreferring to detecting unused spectrum. Cognitive radios attempt tosense “spectrum holes”. A spectrum hole is a frequency range, where theabsence of primary users has been determined. Primary users are forexample TV stations, wireless microphones or cellular systems. Detectingthe absence of primary users is a difficult task and a single detectormay make errors when determining whether the spectrum is primary free ornot. Efficient spectrum use in the cognitive radio bands also requirescoexistence between secondary users.

In passive coexistence methods a cognitive radio selects an operationfrequency or transmission time based on sensing the channel. Activecoexistence, where cognitive radios can share the characteristics andsensing information with other cognitive radios, is expected to enablemore efficient spectrum use than passive coexistence methods.

SUMMARY OF THE INVENTION

Various aspects of examples of the invention are set out in the claim.

According to a first aspect, there is provided a method, comprising:receiving, by a coexistence node, information on network propertiesassociated with at least one secondary cognitive radio resource user,and sending an upload message, the upload message comprising for asecondary user database at least information on the received networkproperties associated with at least one secondary cognitive radioresource user.

According to a second aspect, there is provided a method, comprising:receiving, by a secondary user database entity, information on networkproperties associated with one or more secondary cognitive radioresource users for a secondary user database, forming location-dependentnetwork map information at least on network properties, and sending thenetwork map information to assist one or more secondary cognitive radioresource users.

According to a third aspect, there is provided an apparatus comprisingat least one processor and at least one memory including computerprogram code, the at least one memory and the computer program codeconfigured to, with the at least one processor, cause the apparatus atleast to perform: receive information on network properties associatedwith one or more secondary cognitive radio resource users, and send anupload message, the upload message comprising for a secondary userdatabase at least information on the received network propertiesassociated with one or more secondary cognitive radio resource users.

According to a fourth aspect, there is provided an apparatus comprisingat least one processor and at least one memory including computerprogram code, the at least one memory and the computer program codeconfigured to, with the at least one processor, cause the apparatus atleast to perform: receive information on network properties associatedwith one or more secondary cognitive radio resource users for asecondary user database, form location-dependent network map informationat least on network properties, and send the network map information toassist one or more secondary cognitive radio resource users.

The invention and various embodiments of the invention provide severaladvantages, which will become apparent from the detailed descriptionbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of example embodiments of the presentinvention, reference is now made to the following descriptions taken inconnection with the accompanying drawings in which:

FIG. 1 illustrates a system with cognitive radio resource user devices;

FIG. 2 illustrates upload operations according to an embodiment;

FIG. 3 illustrates a method according to an embodiment;

FIG. 4 illustrates examples related to network management;

FIGS. 5 and 6 are examples of network arrangements according to someembodiments;

FIGS. 7 to 9 to are flow diagrams according some embodiments; and

FIG. 10 illustrates an apparatus according to an embodiment.

DETAILED DESCRIPTION

FIG. 1 illustrates entities related to cognitive radio (CR) resourceusage according to an example embodiment. The illustrative andsimplified system comprises a plurality of wireless networks 20, 22, 24,26, such as a cellular or non-cellular radio access network (RAN), anIEEE wireless local area network or another network operating on one ormore cognitive radio bands, for instance. The wireless network 20, 22,24 may comprise a number of network elements and terminals connected tothe wireless network.

The example system of FIG. 1 comprises at least one coexistence node 10,16, which is arranged to communicate with at least one database entity30, 34 storing information on CR users. The coexistence node 10 may be amesh point or a radio access network element, such as an access point ora base station (controller) serving a number of (end user) terminals. Insome embodiments mobile terminals are configured to connect a databaseentity 30, 34 and may thus function as coexistence nodes. For instance,the coexistence node 16 may be a terminal device connected to the radionetwork 24.

A system 26, such as a broadcast system, a cellular system, or ashort-range radio system, may act as a primary (CR spectrum) user havinga priority for a given radio resource. Radio devices of such system maythus function as primary users of a given cognitive radio band.

Devices of a non-primary system function as secondary CR spectrum users,which are in the following description recited simply as secondaryusers. In the example of FIG. 1, at least devices 12, 14 may function assecondary users. A secondary user refers generally to a node or networkwhich is using spectrum allowed for non-primary use or planning to usesuch non-primary spectrum, for instance by searching for availablefrequency channels suitable for operation and/or searching for networkopportunities in the area. A secondary user may thus be any device or aset of devices capable of using cognitive radio spectrum flexibly, suchas a terminal capable of connecting to one or more networks 20, 22, 24or forming a new network, such as a mesh point, or a network elementserving terminals, such as an access point or a base station. Thecoexistence node 10 may in one embodiment function as a secondary user.

The secondary users 12, 14 need to be able to detect primary users andavoid causing interference to the primary users. The secondary users 12,14 may collaborate in spectrum sensing, by sending spectrum sensinginformation to other nearby secondary users. This may be referred to asdistributed CR coexistence. Thus, when a secondary user 12, 14 has madespectrum sensing, it can provide the detection result for othersecondary users. Then a receiving secondary user may combine its owndetection result and the received detection results. This combineddetection result may be used to estimate whether a CR band is availablefor use.

Information on primary users may also be stored in a database 36,hereafter referred to as a primary user database. This may be referredto as (at least partly) centralized CR coexistence. For instance, thedatabase entity 34 may be a repository service entity arranged tomaintain the primary user database 36 and information on primary users.The secondary users 12, 14 and/or the coexistence node(s) 10, 16 mayreceive information related to spectrum usage by primary users from theprimary user database 36.

The key function of coexistence methods is to enable coexistence betweendifferent users in a band in a way that the spectrum is usedefficiently. The coexistence node 10 may now be configured to receivecoexistence related information from secondary users 12, 14 and providesuch secondary user coexistence related information for a database 32 onsecondary users 12, 14, hereafter referred to as the secondary userdatabase.

In the example of FIG. 1, the database (DB) entity 30, which can be anydatabase access device and may also be referred to as a secondary userDB entity, comprises or is connected to the secondary user database 32.The secondary user DB entity 30 may be responsible for maintaining thesecondary user database 32 and store and retrieve information onsecondary users 12, 14 in the secondary user database 32. The DB entity30 may further process the information before storing it in thesecondary database 32 and/or before sending information for secondaryusers 12, 14.

The active sharing of secondary CR user information and application of aspecific secondary user database facilitates further efficient CRspectrum use and discovery of secondary CR networking possibilities.

The coexistence node 10 may act on behalf of at least one secondary user12, 14, such as network elements of a given network, and arrange thecommunication between secondary users and the secondary user DB entity30. Thus, it is not necessary for the secondary users 12, 14 to havemeans for directly communicating with the secondary user DB entity 30,but the coexistence node may (locally) communicate appropriatecoexistence related information in an appropriate form with thesecondary users 12, 14. It is to be noted that it may be possible thatsome networks directly connect the secondary user DB entity 30 withoutusing a coexistence node or send and/or receive secondary userinformation via one or more further secondary user networks andassociated coexistence node.

In one embodiment the secondary user DB entity 30 is connected to theprimary user database entity 34 to have access to primary userinformation. Thus, information on primary users may also be provided forsecondary users by the secondary user DB entity 30, and it is notnecessary to separately connect the primary user database entity 34.FIG. 2 illustrates a method, which may be carried out by the coexistencenode 10, for instance. Information at least on network propertiesassociated with nearby secondary cognitive radio resource users 12, 14is received 200. For instance, the coexistence node 10 may be arrangedto gather network property information from one or more radio devices ofat least one network functioning as a secondary user. At least some ofthis information may be stored in a memory of the coexistence node andreceived in step 200 from the memory.

In step 210 an upload message is generated, the upload messagecomprising for a secondary user database at least information on thereceived network properties associated with nearby secondary cognitiveradio resource users. The upload message refers generally to any type ofmessage suitable for transferring network property information forstoring in the secondary user database. For instance, the coexistencenode 10 sends the upload message to the database entity 30 which furtherprocess the information and update the secondary user database with thecurrent network situation. It is to be noted that the coexistence nodeand the secondary user DB entity 30 could be implemented even in asingle physical device, such as an access point. Thus, in some cases thesending of the upload message refers to sending of network propertyinformation between entities of a single device.

In one embodiment, the coexistence node 10 is arranged to gather, byactively requesting and/or passively receiving, information regardingnetworks with similar properties or of similar type as the network 20 ofthe coexistence node 10. For instance, the coexistence node 10 may bearranged to detect identifiers of other similar standard networks andinclude 210 information associated with such identifiers in the uploadmessage.

In one embodiment the coexistence node 10 is arranged to form acommunication map on the basis of the received network properties ofneighboring secondary users 12, 14. The communication map representsreal information of neighboring cognitive radio networks, which may usethe same or different underlying radio access technology. Thecoexistence node 10 may send the communications map in the uploadmessage to update the secondary user database 32.

The network property information, in a communication map or anotherform, may include at least one or more of the following identificationof a secondary user, for instance a name, an address or anotheridentification of a network, technology or type identification, such asthe used standard(s) or access type(s), transmit power, operatingfrequency, priority information, network location information,compatibility information, network size information, information onprovided services, quality of service information such as average accessdelay, access establishment related information, and utilizationcharacteristics. For instance, the utilization characteristics couldinclude information on channel utilization ratio and/or periodicalactivity, such as activity start time, active time, interval to nextactivity start.

FIG. 3 illustrates a method, which may be carried out by the DB entity30, for instance. Information at least on network properties associatedwith secondary users is received 300 and stored in the secondary userdatabase 34 as such or at least partly in modified form. For instance,the network property information may be received in a form of acommunication map illustrated above. A location-dependent network mapmay be generated 310 on the basis of the received information. Thenetwork map refers generally to any form of information indicating atleast some networks and network properties in a given area. The networkmap may be generated in response to a request, whereby there may befurther steps of storing the received network property information,receiving a request for location-dependent network map, and retrievingthe network property information before entering step 310.

Network map information is sent 320 to one or more secondary users 12,14 directly or via the coexistence node 10. It will be appreciated thatinstead of an entire network map only a portion of the network map maybe sent. Further, information on configuration actions by thecoexistence node 10 based on the network map information may be sent instep 320. The network map information further assists the secondaryusers 12, 14 to identify and select currently available CR networkingoptions.

The network map may comprise various network property relatedinformation to assist secondary users 12, 14. For instance, a secondaryuser 12, 14 may utilize the network map information to detect currentlyavailable cognitive radio networking options or select a channel for anew network or a better channel for existing operation. The network mapmay comprise at least partly the same information items as indicatedabove for the communication map. In one embodiment the network map maythus comprise at least one of identification of a secondary user, forinstance a name, an address or another identification of a network,technology or type identification, such as the used standard(s) oraccess type(s), transmit power, operating frequency, priorityinformation, network location information, compatibility information,network size information, information on provided services, quality ofservice information such as average access delay, access establishmentrelated information, and utilization characteristics. For instance, thenetwork map may simply comprise a list of locally accessible networks.However, it will be appreciated that the network map may comprisevarious further network related information.

Let us now study some further detailed embodiments related to arrangingthe secondary user database related functions and applying secondaryuser data.

The secondary database 32 may store various information related to thesecondary users, available networks and radio resources. Secondary users12, 14 may report their own operation parameters and othercharacteristics which can be gathered and sent to the DB entity 30 bythe coexistence node 30.

When updating secondary user related information, such as networkproperties, to the secondary user database 32, also further informationmay be included, such as the origin identifier and location of theinformation. In some cases an identifier of the information distributoris different from the origin. In addition the secondary user databasemay have some further information of the environment in question andsignal propagation in such environment. The DB entity 30 may be arrangedto construct the location dependent information for a secondary user 12,14 on the basis of the location of the secondary user, information fromthe primary user database 36, information in the secondary database 32,and/or other information that it may have, such as the propagationmodels or further information on the environment in question.

Spectrum Management Based on Secondary User Information

The secondary users 12, 14 and the coexistence node 10 may be arrangedto send information on spectrum sensing results regarding the currentradio environment to update the secondary database 32. These sensingresults may include sensed information regarding other secondary users12, 14 and/or primary users 26. The sensing results may includeinformation such as one or more of estimate of channel occupancy (free,occupied, unknown, for instance), average or peak received signalstrength indicator (RSSI) characteristics on the channel, utilization ofthe activity (high, medium, or low, unknown, for instance),utilization-%, or possible time characteristics of the activity, type ofsensed interference (unknown, radio standard type, for instance).

In one embodiment the sensing information, such as one or more of theabove information items, for the secondary user database 32 is includedin a spectrum sensing map. Each secondary user may form a sensing map ofits sensing results, send the sensing map to the secondary user databaseentity 30 directly or via the coexistence node 10. Alternatively, thecoexistence node 10 may form a sensing map including sensing results ofa plurality of secondary users and send the sensing map to the secondaryuser database entity 30. In a still further embodiment the spectrum mapis generated by the secondary user database entity 30 on the basis ofsensing information from the secondary users.

In one embodiment the database entity 30, managing the spectrum use orstoring information which enables secondary spectrum users 12, 14 tofind good spectrum opportunities, has (access to) the overall knowledgeof the spectrum use situation. The database entity 30 may have access tothe primary user information in the primary user database 36, and thisprimary user information may be delivered to the secondary users andtaken into account for spectrum decisions. Based on receivedlocation-specific information on secondary users 12, 14, such as thenetwork property information and the sensing information, and primaryuser information from the primary user database 36, the DB entity 30 maycalculate optimal spectrum allocations for different locations, and alsodetermine the areas in which different networks are accessible to thespectrum users 12, 14. With this information the DB entity 30 may assistsecondary users on the optimal spectrum resources to use (frequencies,times, etc.), and/or which networks are accessible in the area of thesecondary users. Instead of merely assisting in spectrum use, the DBentity 30 may be arranged to command the secondary users to use only theallocated spectrum resources.

In one embodiment a location-dependent spectrum map is generated basedon information at least on spectrum usage of secondary users. Thespectrum map or a relevant/requested portion of the spectrum map may besent for one or more secondary users 12, 14. In the example of FIG. 1,the DB entity 30 may be arranged to download the spectrum map to one ormore secondary users 12, 14 directly or via the coexistence node 10 inresponse to a request or automatically. The DB entity 30 needs to knowthe location for which it constructs the map, i.e. the location of thesecondary user 12, 14 which needs the information.

The spectrum map may comprise at least some of the following informationfor each channel or a set of channels: channel occupancy or utilization(free, high, medium, low, or in %, for instance), technologies (usedstandards or access technology, for instance), type/source ofinterference (primary, secondary), level of interference (very high,high, medium, low, very low, for instance), conflict information, andutilization type of interference (possible time periodicity, forinstance). Channel information for the spectrum map may be gained by atleast one of reported or allocated usage of the channel by a secondaryuser, use of the channel measured or detected by other means by asecondary user, and primary user information from the primary database36. The spectrum map may indicate how information (in a portion of) aspectrum map was acquired. The spectrum map may be determined to bevalid for a given time interval. The validity may be specified on thebasis of time stamps in the received measurements, for instance.

In one embodiment a confidence or reliability indicator is applied toindicate confidence of the secondary user related information. Thisconfidence indicator may be included in the spectrum map and/or thenetwork map, for instance. In one embodiment the confidence indicatorindicates how reliably a channel in a spectrum map is classified as busyor free, for instance. The confidence indicator may be dependent on thedistance or location of the reporting entity 10, 12 reporting on the useof a channel to the secondary user 10, 12 actually using the channel.For instance, 100% confidence can be indicated in case the channel wasused in the very close vicinity of the point where it was reported to beused or if a secondary user 12, 14 reported its own usage. A valuebetween 50 to 90%, for instance, could be indicated for a channel usedfurther away from the point where it was reported to be used. In case alocation of an actual user is reported, then also a reporter sendingsensing results may report its location for the DB entity 30 or adaptfurther information, such as the confidence indicator value based on itslocation. Location or distance information for generating the confidenceindicator may be included in the upload message 210 or the sensing map,for instance. Applied sensing method or length of sensing period mayalso be applied for defining confidence indicator value.

Depending on the network scenario, the secondary user 12, 14 may be anode or a network. Also the coexistence node 10, 16 may function as asecondary user. For instance, if the network is a local network, anaccess point or a fusion center may upload and access secondary userinformation on behalf of the whole network. In this case the nodes maynot see very different spectrum situation. If the network is a widerarea network, secondary user information may be collected by thecoexistence node 10, 16 from a plurality of secondary users, becausespectrum situation in each location may be very different. In the casethat a node is not associated to any network, for instance since it islooking for network opportunities, it may connect the DB entity 30 toobtain secondary user information.

The secondary spectrum user 12, 14 may be arranged to use theinformation from the secondary user database 32 for discovering networkopportunities or spectrum opportunities. For network discovery thesecondary user needs to know network technologies, and identification,and on which channels the networks reside. For the spectrum opportunitydetection the spectrum user needs to know what type of interferencethere is in the channels. The spectrum user 12, 14 may request thesecondary database entity 30 to provide specifically identifiedinformation, such as a specific network map or spectrum map or portionthereof with identified information. However, it is important to notethat the information of at least some of such maps may also be combinedinto one map.

The connection between the secondary users 12, 14, the coexistence node10, and the DB entity 30 may be of various types. A fixed connection maybe used if the secondary user is an access point or a base station, forinstance. A wireless connection may be used in case of mobile nodes. Amobile node may connect to the coexistence node 10 by utilizing awireless local area network access point or a cellular network, forinstance. A (secondary) traffic radio from an already establishednetwork may be applied. In this case the node may be using the secondaryradio with some other node via which it accesses the DB. The secondaryuser 12, 14 may start to communicate by using the (secondary) trafficradio, and change to another radio after interference information hasbeen received. In this example the secondary user 12, 14 may connect tothe DB entity 30 or the coexistence entity 10 by one radio, and changeto use another radio on the basis of received secondary user databaseinformation.

Centralized Secondary Database Entity Functionality

The DB entity 30 maintaining at least the secondary user database 32 maybe a centralized entity which may store, obtain, and share secondaryuser related information. Thus, discovery of available networkingoptions for secondary users may be centralized. The centralized entitymay take care of spectrum allocations on behalf of secondary users 12,14.

In one embodiment decision making regarding secondary users is performedin connection with the secondary user database 32, for instance by theDB entity 30. The DB entity 30 may comprise a spectrum manager. Asecondary user may register to the DB entity 30, and inform the DBentity 30 of required spectrum resources, by sending a resource requestto the spectrum manager, for instance. The spectrum manager in the DBentity 30 may then allocate spectrum for the spectrum user, and thespectrum user shall operate accordingly or report of the change in thespectrum situation or spectrum need.

FIG. 4 illustrates some examples of interaction between secondary usersand the secondary user database entity with a spectrum manager.Secondary users may report measurement information, such as informationfor or in a sensing map and/or communications map regularly or uponchange. The coexistence node 10 may act on behalf of one or moresecondary users, such as network elements of a given network and arrangethe communication between the secondary user(s) and the secondary userDB entity 30. A secondary user may report its spectrum needs or requestspecific CR band. The DB entity 30 may comprise a spectrum managercalculating optimal spectrum use and authorizing and updating spectrumaccess to a secondary user, including frequency, TX power, possible timeparameters, for instance.

Distributed Secondary Database Entity Functionality

In some embodiments the secondary user DB entity 30 functionality isdistributed and a plurality of secondary user databases 32 ismaintained. For instance, a secondary user DB entity 30 may reside ineach network or each group of networks. In this case such DB entity ineach network or group of networks may receive secondary user informationfrom neighboring networks or groups of networks.

Based on its own information and received information, each DB entity 30can calculate optimal spectrum resources and determine accessiblenetworks for the area of its own networks. A DB entity 30 may beoptionally also arranged to perform these functions for networks orgroup of networks from which it received secondary user information.This approach is useful in shared decision making on spectrum allocationand accessible networks. For instance, a DB entity which first discoverschange in spectrum use, which may be caused by introduction of a primaryspectrum user or need for more or less resources by some network, forinstance, is able to calculate the most optimal spectrum use for all. Inthis case the DB entity shares the new spectrum allocations instead ofjust sharing the information that there are conflicts in spectrum use.

In one embodiment decision making regarding secondary users isdistributed. The DB entity 30 may operate only as a proxy betweennetworks 20, 22, 24. Decision making regarding secondary user radioresources may be distributed to the coexistence nodes 10, 16 and/or thesecondary users 12, 14. The DB entity 30 may assist the relevant nodes10, 16 and networks to negotiate directly with each other about thespectrum use. The DB entity 30 may determine inter-relations betweennetworks, for instance which networks are on same channel/band and areaand should negotiate. For instance, the database entity 30 may bearranged to guide a new network during an initialisation phase to samechannels with similar networks, enabling easier channel coexistence. Afurther example is that a DB entity 30, 34 is arranged to provideprimary user information, but regarding secondary user information itmay be arranged only to store and provide identification information,such as an address, of the secondary spectrum users nearby with which asecondary user may want to negotiate.

Example Database Structures

The database 32 comprising the secondary user information may bestructured in different ways. In one embodiment local secondary userdatabases (may also be local databases by different service providers)collect the secondary user information and may also synchronize withother databases. A secondary user 12, 14 may be arranged to access adatabase of its own service provider, for instance. Secondary userdatabases may also be system (technology) specific and/or area specific.For instance, if a secondary user 12, 14 is interested of spectrum useof wide area users it accesses one secondary user database, and if it isinterested of the spectrum use of local area users it accesses anothersecondary user database.

In one embodiment local secondary user databases upload the relevantinformation of secondary users in an upper level or global database.Such global database may also comprise primary user information. Thelocal databases may access the global database to obtain informationrelated to primary spectrum use, and possibly the information of thesecondary use as well. Thus, the local databases and different serviceproviders may access the secondary user information collected by otherlocal databases and other service providers. Hence, the secondary userdatabase 32 may be operator independent, part of operator's network, orindependent and part of an operator's network.

TV White Space System Application Examples

In one embodiment at least some of the above illustrated features areapplied in connection with television white space (TVWS) arrangements,specified by the IEEE. For instance, at least some of the presentlydisclosed features may be applied in connection with the systemarchitecture developed under IEEE 802.19.1. The coexistence node 10 maybe a coexistence enabler (CE) and the one or more secondary cognitiveradio resource users may be TV white space (network) devices. Thesecondary user DB entity may be a coexistence manager (CM) arranged tomanage the spectrum use of one or more TVWS networks, and negotiate withor command other CMs about the spectrum resources use of their managednetwork(s). The secondary spectrum user may be a TVWS network, and theCE entity may represent the network to the coexistence manager. The CEentity may collect the secondary user information, such as the networkproperties, from one or more networks, as illustrated above for thecoexistence node 10. The TVWS device comprising the CE entity may alsocommand the network to act according the spectrum allocations receivedfrom the CM. Various devices may be adapted to act as secondary TVWSusers, for instance: wireless regional area network (WRAN), cellular,WLAN, Femto cell, personal area network (PAN), or a wireless microphonedevices.

FIG. 5 illustrates an example of a centralized architecture, in whichthe secondary user database 32 may be included in (or connected to) a CMdevice 500. A plurality of TVWS networks and respective CE entities 510are connected to the CM device. Each CE entity 510 may send thesecondary user related information, such as the network propertyinformation, to the CM, which may determine available networks in eachlocation and may also determine optimal spectrum location in eachlocation. The sixth TVBD network 530 is not connected to the CM 500. Ifthe fifth network 540 is of same technology as the sixth network 530and/or is able to query network 6 530 operating parameters directly, theCE entity of the fifth network 540 may be arranged to send thoseparameters to the CM 500 as a communication map. Otherwisecharacteristics of the sixth network 530 are only detected by sensingand may be included in a sensing map to the CM 500.

FIG. 6 provides an example, in which some networks 600, 602, 606 in anarea are independent and some networks 610, 612, 614 are centrallymanaged. As illustrated in FIG. 6, in one embodiment independentnetworks 600, 602, ad 606 may comprise both CE and CM entities, whichmay be located in a single device. In one embodiment two or more CMs areconnected and may share secondary user information. In FIG. 6, the CM620 may be connected to the CM 630 of the managed networks and canreceive the secondary user information from the CM 630. The CM 630 maytake into account the spectrum usage and/or network property informationsend to it, for instance detected characteristics of the independentnetworks 600 and 602. Thus, networks 612 close to the independentnetworks 600, 602 may be allocated with resources which networks 1 and 2should not interfere.

The secondary user database 32 can be included in connection with otherservices or databases. In one example the secondary user database isarranged in or in association with a media portal or map informationdatabase. In addition to updating current location, a terminal may alsoupload information related to the location such as pictures taken at thelocation, and download information related to locations, such asrestaurants nearby. For instance, spectrum situation or network propertyinformation a terminal sees in its location is also information relatedto the location. The terminal may upload also such secondary userrelated information to a map server. Similarly, the terminal could alsodownload location related spectrum and network map information which maycontain also primary user information. For instance, the map serviceprovider may also function as a white space service provider (WSSP)providing an available channel list, i.e. a list of channels free fromregistered primary users, to secondary users.

Signalling Examples

FIG. 7 illustrates some examples of messages which may be applied toupdate secondary user related information from the coexistence node 10to the DB entity 30. An update message may comprise, for at least onesecondary user 12, 14, one or more of location information, owncharacteristics, sensing map, and communication map, associated withidentifier(s) of respective secondary users(s). Instead of applyingseparate messages as illustrated in FIG. 7, updating information may bemerged in one or less messages. In case of distributed secondary userdatabases, the updates may be sent between secondary user DB entities,such as the TVWS CMs.

In one embodiment information of the secondary user database is sentautomatically. The DB entity 30 may send all or some of the aboveindicated information, for instance the spectrum map to the coexistencenode 10 or other node supporting coexistence in response to a trigger.FIG. 8 illustrates an example of automatic transmission of spectrum mapupdate 804 and a network map update 806 from a DB entity 30, such as aTVWS CM. The secondary user database information may be sentautomatically, for instance, in case the spectrum map has changed 802,and/or the change may affect a spectrum user. The DB entity 30 shouldknow the location of a target spectrum user in order to construct themap for the right positions. The DB entity 30 may know the location ofthe secondary spectrum user if the spectrum user updates its locationregularly or upon change. Further, in case of access points, thelocation typically does not change often.

FIG. 8 illustrates an example of a centralized case in which theinformation 804, 806 is sent to a coexistence node 10, such as a TVWSCE. In case of distributed DB entities, the updates may be transferredbetween DB entities, such as TVWS CMs.

In another embodiment the information from the secondary user database32 is sent upon request. FIG. 9 illustrates message exchange forgenerating 902, 908 and sending 904, 910 a spectrum map and a networkmap upon respective requests 900, 906. Again, in case of a distributedsecondary user databases, the updates may be sent between secondary userDB entities, such as the TVWS CMs.

Example Apparatus

FIG. 10 is a simplified block diagram of high-level elements of anapparatus according to an embodiment. The apparatus comprises a dataprocessing element DP 100 with at least one data processor, at least oneradio frequency transceiver 110 with a transmitter 114 and a receiver112, and a memory 120 storing a program 122. The apparatus may beconfigured to function as the coexistence node 10, a secondary user 12,14, or the DB entity 30 and carry out at least some of theabove-indicated functions associated with such entity. Thus, theapparatus may be a database controller, an access point, a base station,a radio access controller, a network manager device, or another type ofdevice with cognitive radio related features, for instance.

The memory 120 may be of any type suitable to the technicalimplementation context of the respective entity and may be implementedusing any suitable data storage technology. The data processing element100 may be of any type suitable to the local technical environment, andmay include one or more of general purpose computers, special purposecomputers (such as an application-specific integrated circuit (ASIC) ora field programmable gate array FPGA), microprocessors, digital signalprocessors (DSPs) and processors based on a multi-core processorarchitecture, as non-limiting examples.

In general, various embodiments of the presently disclosed features maybe implemented by computer software stored in a computer-readablemedium, such as the memory 120 and executable by the data processingelement 100 of the apparatus, or by hardware (such as an ASIC), or by acombination of software and/or firmware and hardware in the apparatus.

In the context of this document, a “computer-readable medium” may be anymedia or means that can contain, store, communicate, propagate ortransport the instructions for use by or in connection with aninstruction execution system, apparatus, or device, such as a computer,with one example of a computer described and depicted in FIG. 10. Acomputer-readable medium may comprise a computer-readable storage mediumthat may be any media or means that can contain or store theinstructions for use by or in connection with an instruction executionsystem, apparatus, or device, such as a computer.

The program 122 may comprise computer program instructions that, whenexecuted by a data processor 100, enable the cognitive radio terminal 10to operate in accordance with at least some of embodiments of thepresent invention. The program may comprise computer program codeconfigured to, with the at least one processor, cause the apparatus toperform at least some of the features illustrated in connection withFIGS. 1 to 9.

The apparatus could be in a form of a chip unit or some other kind ofhardware module for controlling a cognitive radio device. The hardwaremodule may form part of the device and could be removable. Some examplesof such hardware module include a sub-assembly or an accessory device.

For instance, the secondary user 12, 14, the coexistence node 10, or theDB entity 30 of FIG. 1 may comprise the elements of FIG. 10. It will beappreciated that the apparatus may comprise various further elements notdiscussed in detail herein.

Although the apparatus and the data processing element 100 are depictedas a single entity, different features may be implemented in one or morephysical or logical entities. There may be further specific functionalmodule(s), for instance for carrying one or more of the steps describedin connection with FIG. 2 or 3.

The apparatus of FIG. 10 may be arranged to use licensed and/orunlicensed bands. It should be appreciated that the above-illustratedembodiments related to sharing secondary user related information may beapplied in any current or future standard or non-standard radio systemthat supports cognitive radios. As non-limiting examples, the apparatusmay be configured to operate in or as part of a wireless local areanetwork (WLAN), code division multiple access (CDMA), orthogonalfrequency-division multiple access (OFDMA), UMTS terrestrial radioaccess network (UTRAN) or evolved UTRAN (E-UTRAN) based wirelesscommunication system. The apparatus may be arranged to support one ormore CR technologies to communicate secondary user information withanother communications device. For instance, the apparatus may bearranged to support any of IEEE cognitive radio related specifications,such as specifications of the IEEE 802.22 or 802.11 working group, ThirdGeneration Partnership Project (3GPP) long term evolution (LTE)cognitive radio features or ECMA-392 cognitive radio features. However,it will be appreciated that the application of the present features isnot limited to any particular cognitive radio technologies.

If desired, at least some of the different functions discussed hereinmay be performed in a different order and/or concurrently with eachother. Furthermore, if desired, one or more of the above-describedfunctions may be optional or may be combined.

Although various aspects of the invention are set out in the independentclaim, other aspects of the invention comprise other combinations offeatures from the described embodiments and/or the dependent claim withthe features of the independent claim, and not solely the combinationsexplicitly set out in the claim.

It is also noted herein that while the above describes exampleembodiments of the invention, these descriptions should not be viewed ina limiting sense. Rather, there are several variations and modificationswhich may be made without departing from the scope of the presentinvention as defined in the appended claim.

1. A method, comprising: receiving, by a coexistence node, informationon network properties associated with at least one secondary cognitiveradio resource user, and sending an upload message, the upload messagecomprising for a secondary user database at least information on thereceived network properties associated with the at least one secondarycognitive radio resource user.
 2. The method of claim 1, wherein thecoexistence node generates a communication map on the basis of thereceived information on network properties, and the coexistence nodesends the communication map in the upload message to a secondary userdatabase.
 3. The method of claim 1, further comprising: receiving, bythe coexistence node, information on sensed radio resource usage fromone or more secondary cognitive radio users, and transmitting theinformation on sensed radio resource usage for the secondary userdatabase.
 4. A method, comprising: receiving, by a secondary userdatabase entity, information on network properties associated with oneor more secondary cognitive radio resource users for a secondary userdatabase, forming location-dependent network map information at least onnetwork properties, and sending the network map information to assistone or more secondary cognitive radio resource users.
 5. The method ofclaim 4, further comprising: receiving, by the secondary user databaseentity, information at least on spectrum usage of one or more secondarycognitive radio resource users for a secondary user database, forming alocation-dependent spectrum map on the basis of the receivedinformation, the spectrum map comprising at least information onspectrum usage, and sending the spectrum map to one or more secondarycognitive radio resource users.
 6. The method of claim 4, wherein thenetwork map information comprises at least one of networkidentification, type or technology identification, transmit power,operating frequency, priority information, location information,compatibility information, network size information, information onprovided services, quality of service information, access establishmentrelated information, and utilization characteristics.
 7. The method ofclaim 1, wherein the information on network properties comprises atleast one of identification of a secondary user, network identification,type or technology identification, transmit power, operating frequency,priority information, location information, compatibility information,network size information, information on provided services, quality ofservice information, access establishment related information, andutilization characteristics.
 8. The method of claim 1, wherein thesecondary cognitive radio resource users are television white spacedevices.
 9. An apparatus, comprising: at least one processor; and atleast one memory including computer program code, the at least onememory and the computer program code configured to, with the at leastone processor, cause the apparatus at least to perform: receiveinformation on network properties associated with one or more secondarycognitive radio resource users, send an upload message, the uploadmessage comprising for a secondary user database at least information onthe received network properties associated with one or more secondarycognitive radio resource users.
 10. An apparatus, comprising: means forreceiving information on network properties associated with one or moresecondary cognitive radio resource user, and means for sending an uploadmessage, the upload message comprising for a secondary user database atleast information on the received network properties associated with theone or more secondary cognitive radio resource user.
 11. The apparatusof claim 9, wherein the apparatus is configured to generate acommunication map on the basis of the received information on networkproperties, and the apparatus is configured to send the communicationmap in the upload message to the secondary user database.
 12. Theapparatus of claim 9, wherein the apparatus is configured to receiveinformation on sensed radio resource usage from one or more secondarycognitive radio users, and the apparatus is configured to transmit theinformation on sensed radio resource usage for the secondary userdatabase.
 13. The apparatus of claim 9, wherein the apparatus isconfigured to function as a coexistence enabler and the one or moresecondary cognitive radio resource users are television white spacedevices.
 14. The apparatus of claim 9, wherein the apparatus is a radioaccess network device.
 15. An apparatus, comprising: at least oneprocessor; and at least one memory including computer program code, theat least one memory and the computer program code configured to, withthe at least one processor, cause the apparatus at least to perform:receive information on network properties associated with one or moresecondary cognitive radio resource users for a secondary user database,form location-dependent network map information at least on networkproperties, and send the network map information to assist one or moresecondary cognitive radio resource users.
 16. An apparatus, comprising:means for receiving information on network properties associated withone or more secondary cognitive radio resource users for a secondaryuser database, means for forming location-dependent network mapinformation at least on network properties, and means for sending thenetwork map information to assist one or more secondary cognitive radioresource users.
 17. The apparatus of claim 15, wherein the apparatus isfurther configured to receive information at least on spectrum usage ofone or more secondary cognitive radio resource users for a secondaryuser database, form a location-dependent spectrum map on the basis ofthe received information, the spectrum map comprising at leastinformation on spectrum usage, and send the spectrum map to one or moresecondary cognitive radio resource users.
 18. The apparatus of claim 15,wherein the network map information comprises at least one of networkidentification, type or technology identification, transmit power,operating frequency, priority information, location information,compatibility information, network size information, information onprovided services, quality of service information, access establishmentrelated information, and utilization characteristics.
 19. The apparatusof claim 15, wherein the apparatus is a database access devicecomprising or connected to the secondary user database and configured tocommunicate the cognitive radio resource user related information with acoexistence node of a radio access network.
 20. The apparatus of claim9, wherein the information on network properties comprises at least oneof identification of a secondary user, network identification, type ortechnology identification, transmit power, operating frequency, priorityinformation, location information, compatibility information, networksize information, information on provided services, quality of serviceinformation, access establishment related information, and utilizationcharacteristics.
 21. The apparatus of claim 15, wherein the one or moresecondary cognitive radio resource users are television white spacedevices.
 22. A computer readable storage medium comprising one or moresequences of one or more instructions which, when executed by one ormore processors of an apparatus, cause the apparatus to perform thesteps in claim 1.